1. Field of the Invention
The invention relates to a rear hanging structure for the suspension of a turbojet engine from a mast situated under the wing of an aircraft.
2. Summary of the Prior Art
The hanging of a turbojet engine under the wing of an aircraft may be effected by means of a mast designed to ensure the mechanical transmission of stresses between the engine and the structure of the aircraft. The turbojet engine is suspended from the mast at two points defining a front suspension and a rear suspension. The transmission of the actual thrust forces is achieved by means of inclined thrust take up bars situated on both sides of the engine.
The rear suspension normally comprises at least three outer hanging lugs or yokes which are formed integrally with the upper part of the exhaust casing of the turbojet engine. These lugs allow the exhaust casing to be secured to the lower ends of three suspension links which have their upper ends mounted on a substantially arc-shaped hanging member secured directly under the mast for carrying the engine.
Normally, the arc-shaped rear hanging member comprises a single piece brace to which each link is attached by a horizontal suspension pin. The brace itself is fixed under the mast by screws which are received in two horizontal suspension pins passing through the brace.
French Patent No. 2 599 708 considers the possibility of accidental breakage of one of the links by which the turbojet engine is suspended from the brace of the rear hanging structure, indicating that such a breakage could lead to the total break away of the engine or, at least, to damage to the inclined thrust take-up bars which are situated on opposite sides of the engine. To avoid this problem, it has been proposed to supplement the three suspension links normally used by a fourth link, termed a safety link, which performs a mechanical support role only if one of the three primary suspension links is broken.
However, while Specification No. FR-A-8608336 proposes a satisfactory solution to the problem posed by the breakage of one of the three suspension links by which the turbojet engine is suspended from the brace secured under the mast, it is not concerned with the case where failure of the rear suspension would result from a breakage of the one piece brace normally used. While the occurrence of such a breakage would appear more improbable than the breakage of one of the suspension links, the risk of it leading to the total breaking away of the engine would be much greater.